What kind of neural network architecture is suitable for variable length block-like time series data?
(this response should be a comment but I don't have yet the reputation to comment).

If I'm understanding your problem correctly you have a variable number of input which have an order and only one output ? It look like the kind of task where you could use recurrent neural network (the most common ones are the LSTM and GRU). 

If you use a recurrent neural network you could (if you have the timestamps of your data) cut the hourly interval into smaller time step to help detect pattern.